some fixes/tweaks for MTC slaving, some untested

git-svn-id: svn://localhost/ardour2/branches/3.0@6676 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/ardour/ardour/audioengine.h

@@ -94,6 +94,12 @@ class AudioEngine : public SessionHandlePtr
 		return jack_frame_time (_priv_jack);
 	}
 
+	nframes_t frame_time_at_cycle_start () {
+  	        jack_client_t* _priv_jack = _jack;
+		if (!_running || !_priv_jack) return 0;
+		return jack_last_frame_time (_priv_jack);
+	}
+
 	nframes_t transport_frame () const {
   	        const jack_client_t* _priv_jack = _jack;
 		if (!_running || !_priv_jack) return 0;

libs/ardour/ardour/pi_controller.h

@@ -60,7 +60,7 @@ class PIChaser {
     PIChaser();
     ~PIChaser();
 
-    double get_ratio( nframes64_t realtime, nframes64_t chasetime, nframes64_t slavetime, bool in_control );
+    double get_ratio( nframes64_t chasetime_measured, nframes64_t chasetime, nframes64_t slavetime_measured, nframes64_t slavetime, bool in_control );
     void reset();
     nframes64_t want_locate() { return want_locate_val; }
 

libs/ardour/ardour/slave.h

@@ -264,10 +264,11 @@ class MTC_Slave : public Slave {
 	bool           have_first_speed_accumulator;
 	double         average_speed;
 	Glib::Mutex    reset_lock;
-	bool           reset_pending;
+	uint32_t       reset_pending;
+	bool           reset_position;
 
-	void reset ();
+	void reset (bool with_pos);
-	void queue_reset ();
+	void queue_reset (bool with_pos);
 	void maybe_reset ();
 
 	void update_mtc_qtr (MIDI::Parser&, int, nframes_t);

libs/ardour/mtc_slave.cc

@@ -56,7 +56,8 @@ MTC_Slave::MTC_Slave (Session& s, MIDI::Port& p)
 {
 	can_notify_on_unknown_rate = true;
 	did_reset_tc_format = false;
-	reset_pending = false;
+	reset_pending = 0;
+	reset_position = false;
 
 	pic = new PIChaser();
 	
@@ -67,7 +68,7 @@ MTC_Slave::MTC_Slave (Session& s, MIDI::Port& p)
 	speed_accumulator = new double[speed_accumulator_size];
 
 	rebind (p);
-	reset ();
+	reset (true);
 }
 
 MTC_Slave::~MTC_Slave()
@@ -188,7 +189,7 @@ MTC_Slave::update_mtc_time (const byte *msg, bool was_full, nframes_t now)
 		session.request_locate (mtc_frame, false);
 		session.request_transport_speed (0);
 		update_mtc_status (MIDI::MTC_Stopped);
-		reset ();
+		reset (false);
 		reset_window (mtc_frame);
 
 	} else {
@@ -395,6 +396,7 @@ MTC_Slave::speed_and_position (double& speed, nframes64_t& pos)
 	nframes64_t now = session.engine().frame_time();
 	SafeTime last;
 	nframes_t elapsed;
+	bool in_control = false;
 
 	read_current (&last);
 
@@ -412,7 +414,7 @@ MTC_Slave::speed_and_position (double& speed, nframes64_t& pos)
 		pos = last.position;
 		session.request_locate (pos, false);
 		session.request_transport_speed (0);
-		queue_reset ();
+		queue_reset (false);
 		DEBUG_TRACE (DEBUG::MTC, "MTC not seen for 1/4 second - reset pending\n");
 		return false;
 	}
@@ -420,13 +422,15 @@ MTC_Slave::speed_and_position (double& speed, nframes64_t& pos)
 	DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC::speed_and_position %1 %2\n", last.speed, last.position));
 
 	if (give_slave_full_control_over_transport_speed()) {
-	    bool in_control = (session.slave_state() == Session::Running);
+		in_control = (session.slave_state() == Session::Running);
 		nframes64_t pic_want_locate = 0; 
 		//nframes64_t slave_pos = session.audible_frame();
 		nframes64_t slave_pos = session.transport_frame();
 		static double average_speed = 0;
 		
-	    average_speed = pic->get_ratio (last.timestamp, last.position, slave_pos, in_control );
+		nframes64_t ref_now = session.engine().frame_time_at_cycle_start();
+		average_speed = pic->get_ratio (last.timestamp, last.position, ref_now, slave_pos, in_control );
+  
 		pic_want_locate = pic->want_locate();
 		
 		if (in_control && pic_want_locate) {
@@ -456,7 +460,12 @@ MTC_Slave::speed_and_position (double& speed, nframes64_t& pos)
 
 	/* now add the most recent timecode value plus the estimated elapsed interval */
 
+	if (in_control) {
+		pos = session.transport_frame();
+	} else {
 		pos = last.position + elapsed; 
+	}
+
 	speed = last.speed;
 
 	DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC::speed_and_position FINAL %1 %2\n", last.speed, pos));
@@ -471,34 +480,44 @@ MTC_Slave::resolution() const
 }
 
 void
-MTC_Slave::queue_reset ()
+MTC_Slave::queue_reset (bool reset_pos)
 {
 	Glib::Mutex::Lock lm (reset_lock);
 	reset_pending++;
+	if (reset_pos) {
+		reset_position = true;
+	}
 }
 
 void
 MTC_Slave::maybe_reset ()
 {
-	reset_lock.lock ();
+	Glib::Mutex::Lock lm (reset_lock);
 
 	if (reset_pending) {
-		reset ();
+		reset (reset_position);
 		reset_pending = 0;
+		reset_position = false;
 	} 
-
-	reset_lock.unlock ();
 }
 
 void
-MTC_Slave::reset ()
+MTC_Slave::reset (bool with_position)
 {
+	if (with_position) {
 		last_inbound_frame = 0;
 		current.guard1++;
 		current.position = 0;
 		current.timestamp = 0;
 		current.speed = 0;
 		current.guard2++;
+	} else {
+		last_inbound_frame = 0;
+		current.guard1++;
+		current.timestamp = 0;
+		current.speed = 0;
+		current.guard2++;
+	}
 
 	window_begin = 0;
 	window_end = 0;

libs/ardour/pi_controller.cc

@@ -151,13 +151,15 @@ PIChaser::~PIChaser() {
 }
 
 double
-PIChaser::get_ratio(nframes64_t realtime, nframes64_t chasetime, nframes64_t slavetime, bool in_control ) {
+PIChaser::get_ratio(nframes64_t chasetime_measured, nframes64_t chasetime, nframes64_t slavetime_measured, nframes64_t slavetime, bool in_control ) {
 
-	feed_estimator( realtime, chasetime );
+	feed_estimator( chasetime_measured, chasetime );
-	std::cerr << (double)realtime/48000.0 << " " << chasetime << " " << slavetime << " ";
+	std::cerr << (double)chasetime_measured/48000.0 << " " << chasetime << " " << slavetime << " ";
 	double crude = get_estimate();
 	double fine;  
+	nframes64_t massaged_chasetime = chasetime + (nframes64_t)( (double)(slavetime_measured - chasetime_measured) * crude );
 
+	fine = pic->get_ratio( slavetime - massaged_chasetime );
 	fine = pic->get_ratio( slavetime - chasetime );
 	if (in_control) {
 	    if (fabs(fine-crude) > crude*speed_threshold) {